Hi Michael,
Here is the Test BlendCap with simple alert message.

- Brian

(For standalone curves, I've got _TrimCurve12 script working with Join and second Trim, to "fixup" the Trim problem with 8X trimpoints on the strange open curve.
But merge with open edges and reTrim is being stubborn.)

Edit 1/25/18: Brian removed the test script to avoid confusion. A knowledgeable programmer can easily add an alert message of # of brep edges.